Heat sources for temperatures up to approximately 1000.degree. C. are needed particularly in the technology of block-type thermal power stations for transforming fuel energy into current and heating warmth in small decentralized units. In such cases, the object is high efficiency with small units. Furthermore, low emissions (NO.sub.x and CO) are desirable. Specifically, a heat source with high dependability and a useful life with simple installation and little maintenance are desirable for use in building heating systems. Furthermore, it must be possible to economically manufacture the heat sources in large runs.
U.S. Pat. No. 5,003,349 discloses a Stirling motor with a combustion chamber surrounded by an annular waste gas/air heat exchanger, which is also designated as a recuperator and serves the purpose of transferring exhaust gas heat to fresh air in counterflow. The recuperator is surrounded with a pot-type thermal insulation.
For a high total efficiency, recuperators should be as efficient as possible. If the gas heater is to be used in small block-type thermal power stations, a compact, simple and sturdy construction is required.